Contrary to popular belief, gutters do not cause ice dams.

It is not your gutters fault that the ice dam has formed, it is your insulation.

Ice dams form when melted snow refreezes at roof edges. Anyone who has lived in cold climates has seen ice dams. We’ve enjoyed the sparkling beauty of ice formations built along roof eaves (of other people’s homes). However, most of us don’t stop to understand why these ice bands form until they damage our homes.

Three things are required for an ice dam to form: snow, heat to melt the snow and cold to refreeze the melted snow into solid ice. Ice dams can form when as little as 1 or 2 inches of snow accumulates on a roof – if the roof is poorly insulated and air sealed, and the snowfall is followed by several days of sub-freezing temperatures. Ice dams develop as snow on the upper part of the roof melts. Water runs down the roof slope under the blanket of snow and refreezes into a band of ice at the roof’s edge creating a “dam”. Additional snow-melt pools against the dam and eventually leaks into the building through the roof or roof trim.

The reason ice-dams form along the roof’s lower edge, usually above the overhang, is straight-forward. The upper roof surface (toward the ridgeline) is at a temperature that is above freezing. And the lower part of the roof surface (along the eaves) is below freezing. The upper roof surface is located directly above the living space. Heat lost from the house warms this section of the roof, melting snow in this area. During periods of sub-freezing temperature the lower regions of the roof deck remain at sub-freezing ambient temperatures. Roof overhangs are not warmed by indoor heat-loss.

Insulate the attic.
YOUR ATTIC NEEDS INSULATION!!

Below is an explanation of what an ice dam is and how to prevent them.

What is an ice dam?

An ice dam is a ridge of ice that forms at the edge of a roof and prevents melting snow (water) from draining off the roof. The water that backs up behind the dam can leak into a home and cause damage to walls, ceilings, insulation, and other areas. Figure 1 shows a cross section of a home with an ice dam.

 

What causes ice dams?

There is a complex interaction among the amount of heat loss from a house, snow cover and outside temperatures that leads to ice dam formation. For ice dams to form there must be snow on the roof, and, at the same time, higher portions of the roof’s outside surface must be above 32 degrees F while lower surfaces are below 32. For a portion of the roof to be below 32, outside temperatures must also be below 32. When we say temperatures above or below 32, we are talking about average temperature over sustained periods of time.

The snow on a roof surface that is above 32 will melt. As water flows down the roof it reaches the portion of the roof that is below 32 and freezes. Voila! – an ice dam.

The dam grows as it is fed by the melting snow above it, but it will limit itself to the portions of the roof that are on the average below 32. So the water above backs up behind the ice dam and remains a liquid. This water finds cracks and openings in the exterior roof covering and flows into the attic space. From the attic it could flow into exterior walls or through the ceiling insulation and stain the ceiling finish.

Preventing and dealing with ice dams

In all Northeast communities it is possible to find homes that do not have ice dams. Ice dams can be prevented by controlling the heat loss from the home.

Immediate action

  • Remove snow from the roof. This eliminates one of the ingredients necessary for the formation of an ice dam. A “roof rake” and push broom can be used to remove snow, but be careful it may damage the roofing materials.
  • In an emergency situation where water is flowing into the house structure, making channels through the ice dam allows the water behind the dam to drain off the roof. Hosing with tap water on a warm day will do this job. Work upward from the lower edge of the dam. The channel will become ineffective within days and is only a temporary solution to ice dam damage.

Long-term action

  • First, make the ceiling air tight so no warm, moist air can flow from the house into the attic space.
  • After sealing air leakage paths between the house and attic space, consider increasing the ceiling/roof insulation to cut down on heat loss by conduction.
    Any person on the roof during the winter or performing work on the roof from below is risking injury and risking damage to the roof and house. It is important to contact professionals to carry out this job

Snow, Ice and the extra weight

Ice –  One inch of ice weighs a little less than 5 pounds per square foot, and 1 foot of ice weighs approximately 57 pounds per square foot. Ice weighs significantly more than heavy, wet snow per inch depth. In part, this is why it is important to prevent ice buildup on a roof structure and gutters.  Ice dams are very heavy and dangerous.

This most recent snow fall is putting serious stress on your gutters and the fascia board that they are attached to.  Frozen debris  in gutters will add weight to the gutters increasing the stress, clean your gutters regularly to prevent additional damage. If your gutters are not properly secured or your fascia has begun to deteriorate due to the every day weather conditions your gutters can fall off.  A fallen gutter that is not damaged is not as  bad as a gutter that is hanging and bent.  Once the gutter is bent it can not be repaired.

A yearly gutter maintenance check-up will alert you to any issues that may be going on with your gutters.  Check out the information on our website regarding gutter cleanings, repairs, installations and Service Agreements.

keltomgutters.com    973-852-7100